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Sabbarini IM, Reif D, McQuown AJ, Nelliat AR, Prince J, Membreno BS, Wu CCC, Murray AW, Denic V. Zinc-finger protein Zpr1 is a bespoke chaperone essential for eEF1A biogenesis. Mol Cell 2023; 83:252-265.e13. [PMID: 36630955 PMCID: PMC10016025 DOI: 10.1016/j.molcel.2022.12.012] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2022] [Revised: 11/15/2022] [Accepted: 12/12/2022] [Indexed: 01/12/2023]
Abstract
The conserved regulon of heat shock factor 1 in budding yeast contains chaperones for general protein folding as well as zinc-finger protein Zpr1, whose essential role in archaea and eukaryotes remains unknown. Here, we show that Zpr1 depletion causes acute proteotoxicity driven by biosynthesis of misfolded eukaryotic translation elongation factor 1A (eEF1A). Prolonged Zpr1 depletion leads to eEF1A insufficiency, thereby inducing the integrated stress response and inhibiting protein synthesis. Strikingly, we show by using two distinct biochemical reconstitution approaches that Zpr1 enables eEF1A to achieve a conformational state resistant to protease digestion. Lastly, we use a ColabFold model of the Zpr1-eEF1A complex to reveal a folding mechanism mediated by the Zpr1's zinc-finger and alpha-helical hairpin structures. Our work uncovers the long-sought-after function of Zpr1 as a bespoke chaperone tailored to the biogenesis of one of the most abundant proteins in the cell.
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Affiliation(s)
- Ibrahim M Sabbarini
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138, USA
| | - Dvir Reif
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138, USA
| | - Alexander J McQuown
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138, USA
| | - Anjali R Nelliat
- Graduate Program in Systems Biology, Harvard Medical School, Boston, MA 02115, USA
| | - Jeffrey Prince
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138, USA
| | - Britnie Santiago Membreno
- RNA Biology Laboratory, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Frederick, MD 21702, USA
| | - Colin Chih-Chien Wu
- RNA Biology Laboratory, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Frederick, MD 21702, USA
| | - Andrew W Murray
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138, USA
| | - Vladimir Denic
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138, USA.
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52
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Tomomatsu S, Watanabe A, Tesina P, Hashimoto S, Ikeuchi K, Li S, Matsuo Y, Beckmann R, Inada T. Two modes of Cue2-mediated mRNA cleavage with distinct substrate recognition initiate no-go decay. Nucleic Acids Res 2023; 51:253-270. [PMID: 36583309 PMCID: PMC9841427 DOI: 10.1093/nar/gkac1172] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2022] [Revised: 11/17/2022] [Accepted: 11/25/2022] [Indexed: 12/31/2022] Open
Abstract
Ribosome collisions are recognized by E3 ubiquitin ligase Hel2/ZNF598, leading to RQC (ribosome-associated quality control) and to endonucleolytic cleavage and degradation of the mRNA termed NGD (no-go decay). NGD in yeast requires the Cue2 endonuclease and occurs in two modes, either coupled to RQC (NGDRQC+) or RQC uncoupled (NGDRQC-). This is mediated by an unknown mechanism of substrate recognition by Cue2. Here, we show that the ubiquitin binding activity of Cue2 is required for NGDRQC- but not for NGDRQC+, and that it involves the first two N-terminal Cue domains. In contrast, Trp122 of Cue2 is crucial for NGDRQC+. Moreover, Mbf1 is required for quality controls by preventing +1 ribosome frameshifting induced by a rare codon staller. We propose that in Cue2-dependent cleavage upstream of the collided ribosomes (NGDRQC-), polyubiquitination of eS7 is recognized by two N-terminal Cue domains of Cue2. In contrast, for the cleavage within collided ribosomes (NGDRQC+), the UBA domain, Trp122 and the interaction between Mbf1 and uS3 are critical.
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Affiliation(s)
- Shota Tomomatsu
- Division of RNA and Gene Regulation, Institute of Medical Science, The University of Tokyo, Minato-Ku 108-8639, Japan
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, Bunkyo-Ku, Tokyo, Japan
- Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai 980-8578, Japan
| | - Atsuya Watanabe
- Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai 980-8578, Japan
| | - Petr Tesina
- Gene Center and Department of Biochemistry, Feodor-Lynen-Strasse 25, University of Munich, D-81377 Munich, Germany
| | - Satoshi Hashimoto
- Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai 980-8578, Japan
| | - Ken Ikeuchi
- Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai 980-8578, Japan
- Gene Center and Department of Biochemistry, Feodor-Lynen-Strasse 25, University of Munich, D-81377 Munich, Germany
| | - Sihan Li
- Division of RNA and Gene Regulation, Institute of Medical Science, The University of Tokyo, Minato-Ku 108-8639, Japan
- Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai 980-8578, Japan
| | - Yoshitaka Matsuo
- Division of RNA and Gene Regulation, Institute of Medical Science, The University of Tokyo, Minato-Ku 108-8639, Japan
- Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai 980-8578, Japan
| | - Roland Beckmann
- Gene Center and Department of Biochemistry, Feodor-Lynen-Strasse 25, University of Munich, D-81377 Munich, Germany
| | - Toshifumi Inada
- Division of RNA and Gene Regulation, Institute of Medical Science, The University of Tokyo, Minato-Ku 108-8639, Japan
- Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai 980-8578, Japan
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53
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Decoding of the ubiquitin code for clearance of colliding ribosomes by the RQT complex. Nat Commun 2023; 14:79. [PMID: 36627279 PMCID: PMC9831982 DOI: 10.1038/s41467-022-35608-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Accepted: 12/12/2022] [Indexed: 01/11/2023] Open
Abstract
The collision sensor Hel2 specifically recognizes colliding ribosomes and ubiquitinates the ribosomal protein uS10, leading to noncanonical subunit dissociation by the ribosome-associated quality control trigger (RQT) complex. Although uS10 ubiquitination is essential for rescuing stalled ribosomes, its function and recognition steps are not fully understood. Here, we show that the RQT complex components Cue3 and Rqt4 interact with the K63-linked ubiquitin chain and accelerate the recruitment of the RQT complex to the ubiquitinated colliding ribosome. The CUE domain of Cue3 and the N-terminal domain of Rqt4 bind independently to the K63-linked ubiquitin chain. Their deletion abolishes ribosomal dissociation mediated by the RQT complex. High-speed atomic force microscopy (HS-AFM) reveals that the intrinsically disordered regions of Rqt4 enable the expansion of the searchable area for interaction with the ubiquitin chain. These findings provide mechanistic insight into the decoding of the ubiquitin code for clearance of colliding ribosomes by the RQT complex.
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54
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Baymukhametov TN, Lyabin DN, Chesnokov YM, Sorokin II, Pechnikova E, Vasiliev A, Afonina Z. Polyribosomes of circular topology are prevalent in mammalian cells. Nucleic Acids Res 2022; 51:908-918. [PMID: 36583341 PMCID: PMC9881139 DOI: 10.1093/nar/gkac1208] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Revised: 12/02/2022] [Accepted: 12/06/2022] [Indexed: 12/31/2022] Open
Abstract
Polyribosomes, the groups of ribosomes simultaneously translating a single mRNA molecule, are very common in both, prokaryotic and eukaryotic cells. Even in early EM studies, polyribosomes have been shown to possess various spatial conformations, including a ring-shaped configuration which was considered to be functionally important. However, a recent in situ cryo-ET analysis of predominant regular inter-ribosome contacts did not confirm the abundance of ring-shaped polyribosomes in a cell cytoplasm. To address this discrepancy, here we analyzed the cryo-ET structure of polyribosomes in diluted lysates of HeLa cells. It was shown that the vast majority of the ribosomes were combined into polysomes and were proven to be translationally active. Tomogram analysis revealed that circular polyribosomes are indeed very common in the cytoplasm, but they mostly possess pseudo-regular structures without specific inter-ribosomal contacts. Although the size of polyribosomes varied widely, most circular polysomes were relatively small in size (4-8 ribosomes). Our results confirm the recent data that it is cellular mRNAs with short ORF that most commonly form circular structures providing an enhancement of translation.
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Affiliation(s)
- Timur N Baymukhametov
- Structural biology department, National Research Center ‘Kurchatov Institute’, Moscow 123182, Russia
| | - Dmitry N Lyabin
- Institute of Protein Research RAS, Pushchino, Moscow Region 142290, Russia
| | - Yury M Chesnokov
- Probe and Electron Microscopy Resource Center, National Research Center ‘Kurchatov Institute’, Moscow 123182, Russia
| | - Ivan I Sorokin
- Institute of Protein Research RAS, Pushchino, Moscow Region 142290, Russia
| | - Evgeniya V Pechnikova
- Probe and Electron Microscopy Resource Center, National Research Center ‘Kurchatov Institute’, Moscow 123182, Russia,Electron Microscopy Laboratory, Shubnikov Institute of Crystallography of Federal Scientific Research Centre ‘Crystallography and Photonics’ RAS, Moscow 119333, Russia
| | - Alexander L Vasiliev
- Probe and Electron Microscopy Resource Center, National Research Center ‘Kurchatov Institute’, Moscow 123182, Russia,Electron Microscopy Laboratory, Shubnikov Institute of Crystallography of Federal Scientific Research Centre ‘Crystallography and Photonics’ RAS, Moscow 119333, Russia
| | - Zhanna A Afonina
- To whom correspondence should be addressed. Tel: +7 985 7232812; Fax: +7 4967 318435;
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Helton NS, Moon SL. Is bRaQCing bad? New roles for ribosome associated quality control factors in stress granule regulation. Biochem Soc Trans 2022; 50:1715-1724. [PMID: 36484689 PMCID: PMC11368206 DOI: 10.1042/bst20220549] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2022] [Revised: 11/01/2022] [Accepted: 11/21/2022] [Indexed: 09/04/2024]
Abstract
Maintenance of proteostasis is of utmost importance to cellular viability and relies on the coordination of many post-transcriptional processes to respond to stressful stimuli. Stress granules (SGs) are RNA-protein condensates that form after translation initiation is inhibited, such as during the integrated stress response (ISR), and may facilitate cellular adaptation to stress. The ribosome-associated quality control (RQC) pathway is a critical translation monitoring system that recognizes aberrant mRNAs encoding potentially toxic nascent peptides to target them for degradation. Both SG regulation and the RQC pathway are directly associated with translation regulation, thus it is of no surprise recent developments have demonstrated a connection between them. VCP's function in the stress activated RQC pathway, ribosome collisions activating the ISR, and the regulation of the 40S ribosomal subunit by canonical SG proteins during the RQC all connect SGs to the RQC pathway. Because mutations in genes that are involved in both SG and RQC regulation are associated with degenerative and neurological diseases, understanding the coordination and interregulation of SGs and RQC may shed light on disease mechanisms. This minireview will highlight recent advances in understanding how SGs and the RQC pathway interact in health and disease contexts.
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Affiliation(s)
- Noah S Helton
- The Center for RNA Biomedicine and the Department of Human Genetics, University of Michigan, Ann Arbor, MI 48109, U.S.A
| | - Stephanie L Moon
- The Center for RNA Biomedicine and the Department of Human Genetics, University of Michigan, Ann Arbor, MI 48109, U.S.A
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56
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Jia J, Wang F, Bhujabal Z, Peters R, Mudd M, Duque T, Allers L, Javed R, Salemi M, Behrends C, Phinney B, Johansen T, Deretic V. Stress granules and mTOR are regulated by membrane atg8ylation during lysosomal damage. J Cell Biol 2022; 221:e202207091. [PMID: 36179369 PMCID: PMC9533235 DOI: 10.1083/jcb.202207091] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Revised: 08/02/2022] [Accepted: 08/10/2022] [Indexed: 01/22/2023] Open
Abstract
We report that lysosomal damage is a hitherto unknown inducer of stress granule (SG) formation and that the process termed membrane atg8ylation coordinates SG formation with mTOR inactivation during lysosomal stress. SGs were induced by lysosome-damaging agents including SARS-CoV-2ORF3a, Mycobacterium tuberculosis, and proteopathic tau. During damage, mammalian ATG8s directly interacted with the core SG proteins NUFIP2 and G3BP1. Atg8ylation was needed for their recruitment to damaged lysosomes independently of SG condensates whereupon NUFIP2 contributed to mTOR inactivation via the Ragulator-RagA/B complex. Thus, cells employ membrane atg8ylation to control and coordinate SG and mTOR responses to lysosomal damage.
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Affiliation(s)
- Jingyue Jia
- Autophagy, Inflammation and Metabolism Center of Biochemical Research Excellence, Albuquerque, NM
- Department of Molecular Genetics and Microbiology, University of New Mexico Health Sciences Center, Albuquerque, NM
| | - Fulong Wang
- Autophagy, Inflammation and Metabolism Center of Biochemical Research Excellence, Albuquerque, NM
- Department of Molecular Genetics and Microbiology, University of New Mexico Health Sciences Center, Albuquerque, NM
| | - Zambarlal Bhujabal
- Autophagy Research Group, Institute of Medical Biology, UiT The Arctic University of Norway, Tromsø, Norway
| | - Ryan Peters
- Autophagy, Inflammation and Metabolism Center of Biochemical Research Excellence, Albuquerque, NM
- Department of Molecular Genetics and Microbiology, University of New Mexico Health Sciences Center, Albuquerque, NM
| | - Michal Mudd
- Autophagy, Inflammation and Metabolism Center of Biochemical Research Excellence, Albuquerque, NM
- Department of Molecular Genetics and Microbiology, University of New Mexico Health Sciences Center, Albuquerque, NM
| | - Thabata Duque
- Autophagy, Inflammation and Metabolism Center of Biochemical Research Excellence, Albuquerque, NM
- Department of Molecular Genetics and Microbiology, University of New Mexico Health Sciences Center, Albuquerque, NM
| | - Lee Allers
- Autophagy, Inflammation and Metabolism Center of Biochemical Research Excellence, Albuquerque, NM
- Department of Molecular Genetics and Microbiology, University of New Mexico Health Sciences Center, Albuquerque, NM
| | - Ruheena Javed
- Autophagy, Inflammation and Metabolism Center of Biochemical Research Excellence, Albuquerque, NM
- Department of Molecular Genetics and Microbiology, University of New Mexico Health Sciences Center, Albuquerque, NM
| | - Michelle Salemi
- Proteomics Core Facility, University of California Davis Genome Center, University of California, Davis, Davis, CA
| | - Christian Behrends
- Munich Cluster of Systems Neurology, Ludwig-Maximilians-Universität München, München, Germany
| | - Brett Phinney
- Proteomics Core Facility, University of California Davis Genome Center, University of California, Davis, Davis, CA
| | - Terje Johansen
- Autophagy Research Group, Institute of Medical Biology, UiT The Arctic University of Norway, Tromsø, Norway
| | - Vojo Deretic
- Autophagy, Inflammation and Metabolism Center of Biochemical Research Excellence, Albuquerque, NM
- Department of Molecular Genetics and Microbiology, University of New Mexico Health Sciences Center, Albuquerque, NM
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57
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A distinct mammalian disome collision interface harbors K63-linked polyubiquitination of uS10 to trigger hRQT-mediated subunit dissociation. Nat Commun 2022; 13:6411. [PMID: 36302773 PMCID: PMC9613687 DOI: 10.1038/s41467-022-34097-9] [Citation(s) in RCA: 25] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2022] [Accepted: 10/13/2022] [Indexed: 12/25/2022] Open
Abstract
Translational stalling events that result in ribosome collisions induce Ribosome-associated Quality Control (RQC) in order to degrade potentially toxic truncated nascent proteins. For RQC induction, the collided ribosomes are first marked by the Hel2/ZNF598 E3 ubiquitin ligase to recruit the RQT complex for subunit dissociation. In yeast, uS10 is polyubiquitinated by Hel2, whereas eS10 is preferentially monoubiquitinated by ZNF598 in human cells for an unknown reason. Here, we characterize the ubiquitination activity of ZNF598 and its importance for human RQT-mediated subunit dissociation using the endogenous XBP1u and poly(A) translation stallers. Cryo-EM analysis of a human collided disome reveals a distinct composite interface, with substantial differences to yeast collided disomes. Biochemical analysis of collided ribosomes shows that ZNF598 forms K63-linked polyubiquitin chains on uS10, which are decisive for mammalian RQC initiation. The human RQT (hRQT) complex composed only of ASCC3, ASCC2 and TRIP4 dissociates collided ribosomes dependent on the ATPase activity of ASCC3 and the ubiquitin-binding capacity of ASCC2. The hRQT-mediated subunit dissociation requires the K63-linked polyubiquitination of uS10, while monoubiquitination of eS10 or uS10 is not sufficient. Therefore, we conclude that ZNF598 functionally marks collided mammalian ribosomes by K63-linked polyubiquitination of uS10 for the trimeric hRQT complex-mediated subunit dissociation.
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58
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Pinch M, Muka T, Kandel Y, Lamsal M, Martinez N, Teixeira M, Boudko DY, Hansen IA. General control nonderepressible 1 interacts with cationic amino acid transporter 1 and affects Aedes aegypti fecundity. Parasit Vectors 2022; 15:383. [PMID: 36271393 PMCID: PMC9587632 DOI: 10.1186/s13071-022-05461-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2022] [Accepted: 08/27/2022] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The amino acid transporter protein cationic amino acid transporter 1 (CAT1) is part of the nutrient sensor in the fat body of mosquitoes. A member of the SLC7 family of cationic amino acid transporters, it is paramount for the detection of elevated amino acid levels in the mosquito hemolymph after a blood meal and the subsequent changes in gene expression in the fat body. METHODS We performed a re-annotation of Aedes aegypti cationic amino acid transporters (CATs) and selected the C-terminal tail of CAT1 to perform a yeast two-hybrid screen to identify putative interactors of this protein. One interesting interacting protein we identified was general control nonderepressible 1 (GCN1). We determined the expression pattern of GCN1 in several adult organs and structures using qRT-PCR and western blots. Finally, we knocked down GCN1 using double-stranded RNA and identified changes in downstream signaling intermediates and the effects of knockdown on vitellogenesis and fecundity. RESULTS In a screen for Ae. aegypti CAT1-interacting proteins we identified GCN1 as a putative interactor. GCN1 is highly expressed in the ovaries and fat body of the mosquito. We provide evidence that eukaryotic translation initiation factor 2 subunit alpha (eIF2α) phosphorylation changed during vitellogenesis and that RNA interference knockdown of GCN1 in whole mosquitoes reduced egg clutch sizes of treated mosquitoes relative to controls. CONCLUSIONS Aedes aegypti CAT1 and GCN1 are likely interacting partners and GCN1 is likely necessary for proper egg development. Our data suggest that GCN1 is part of a nutrient sensor mechanism in various mosquito tissues involved in vitellogenesis.
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Affiliation(s)
- Matthew Pinch
- Department of Biology, New Mexico State University, Las Cruces, NM, USA
| | - Theodore Muka
- Department of Biology, New Mexico State University, Las Cruces, NM, USA
| | - Yashoda Kandel
- Department of Biology, New Mexico State University, Las Cruces, NM, USA
| | - Mahesh Lamsal
- Department of Biology, New Mexico State University, Las Cruces, NM, USA
| | - Nathan Martinez
- Department of Biology, New Mexico State University, Las Cruces, NM, USA
| | | | | | - Immo A Hansen
- Department of Biology, New Mexico State University, Las Cruces, NM, USA.
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59
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Brüggenthies JB, Fiore A, Russier M, Bitsina C, Brötzmann J, Kordes S, Menninger S, Wolf A, Conti E, Eickhoff JE, Murray PJ. A cell-based chemical-genetic screen for amino acid stress response inhibitors reveals torins reverse stress kinase GCN2 signaling. J Biol Chem 2022; 298:102629. [PMID: 36273589 PMCID: PMC9668732 DOI: 10.1016/j.jbc.2022.102629] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Revised: 10/07/2022] [Accepted: 10/10/2022] [Indexed: 11/06/2022] Open
Abstract
mTORC1 and GCN2 are serine/threonine kinases that control how cells adapt to amino acid availability. mTORC1 responds to amino acids to promote translation and cell growth while GCN2 senses limiting amino acids to hinder translation via eIF2α phosphorylation. GCN2 is an appealing target for cancer therapies because malignant cells can harness the GCN2 pathway to temper the rate of translation during rapid amino acid consumption. To isolate new GCN2 inhibitors, we created cell-based, amino acid limitation reporters via genetic manipulation of Ddit3 (encoding the transcription factor CHOP). CHOP is strongly induced by limiting amino acids and in this context, GCN2-dependent. Using leucine starvation as a model for essential amino acid sensing, we unexpectedly discovered ATP-competitive PI3 kinase-related kinase inhibitors, including ATR and mTOR inhibitors like torins, completely reversed GCN2 activation in a time-dependent way. Mechanistically, via inhibiting mTORC1-dependent translation, torins increased intracellular leucine, which was sufficient to reverse GCN2 activation and the downstream integrated stress response including stress-induced transcriptional factor ATF4 expression. Strikingly, we found that general translation inhibitors mirrored the effects of torins. Therefore, we propose that mTOR kinase inhibitors concurrently inhibit different branches of amino acid sensing by a dual mechanism involving direct inhibition of mTOR and indirect suppression of GCN2 that are connected by effects on the translation machinery. Collectively, our results highlight distinct ways of regulating GCN2 activity.
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Affiliation(s)
| | | | - Marion Russier
- Max Planck Institute for Biochemistry, Martinsried, Germany
| | | | | | | | | | | | - Elena Conti
- Max Planck Institute for Biochemistry, Martinsried, Germany
| | | | - Peter J. Murray
- Max Planck Institute for Biochemistry, Martinsried, Germany,For correspondence: Peter J. Murray
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60
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Li J, Gao L, Chen J, Zhang WW, Zhang XY, Wang B, Zhang C, Wang Y, Huang YC, Wang H, Wei W, Xu DX. Mitochondrial ROS-mediated ribosome stalling and GCN2 activation are partially involved in 1-nitropyrene-induced steroidogenic inhibition in testes. ENVIRONMENT INTERNATIONAL 2022; 167:107393. [PMID: 35843074 DOI: 10.1016/j.envint.2022.107393] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Revised: 05/30/2022] [Accepted: 07/01/2022] [Indexed: 06/15/2023]
Abstract
In the past 50 years, testosterone (T) level in men has declined gradually. In this research, we discovered that acute exposure to 1-nitropyrene (1-NP), an environmental stressor from polluted atmosphere, reduced T contents by downregulating steroidogenic proteins in mouse testes and Leydig cells. Acute 1-NP exposure caused GCN2 activation and eIF2α phosphorylation, a marker of integrated stress, in mouse testes and Leydig cells. GCN2iB, a selective GCN2 kinase inhibitor, and siGCN2, the GCN2-targeted short interfering RNA, attenuated 1-NP-induced reduction of steroidogenic proteins in Leydig cells. Mechanistically, mitochondrial membrane potential was reduced and ATP5A, UQCRC2, SDHB and NDUFB8, four OXPHOS subunits, were reduced in 1-NP-exposed Leydig cells. Cellular mitochondrial respiration was inhibited and ATP production was reduced. Moreover, mitochondrial reactive oxygen species (ROS) were elevated in 1-NP-exposed Leydig cells. The interaction between GCN2 and uL10, a marker of ribosome stalling, was observed in 1-NP-exposed Leydig cells. MitoQ, a mitochondria-targeted antioxidant, attenuated1-NP-evoked ATP depletion and ribosome stalling in Leydig cells. Moreover, MitoQ suppressed 1-NP-caused GCN2 activation and eIF2α phosphorylation in Leydig cells. In addition, MitoQ alleviated 1-NP-induced steroidogenic inhibition in mouse testes. In conclusion, mitochondrial ROS-mediated ribosome stalling and GCN2 activation are partially involved in environmental stress-induced steroidogenic inhibition in testes.
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Affiliation(s)
- Jian Li
- Key Laboratory of Environmental Toxicology of Anhui Higher Education Institutes, Anhui Medical University, Hefei 230032, China
| | - Lan Gao
- Key Laboratory of Environmental Toxicology of Anhui Higher Education Institutes, Anhui Medical University, Hefei 230032, China.
| | - Jing Chen
- Key Laboratory of Environmental Toxicology of Anhui Higher Education Institutes, Anhui Medical University, Hefei 230032, China
| | - Wei-Wei Zhang
- Key Laboratory of Environmental Toxicology of Anhui Higher Education Institutes, Anhui Medical University, Hefei 230032, China
| | - Xiao-Yi Zhang
- Key Laboratory of Environmental Toxicology of Anhui Higher Education Institutes, Anhui Medical University, Hefei 230032, China
| | - Bo Wang
- Key Laboratory of Environmental Toxicology of Anhui Higher Education Institutes, Anhui Medical University, Hefei 230032, China
| | - Cheng Zhang
- Key Laboratory of Environmental Toxicology of Anhui Higher Education Institutes, Anhui Medical University, Hefei 230032, China
| | - Yan Wang
- Key Laboratory of Environmental Toxicology of Anhui Higher Education Institutes, Anhui Medical University, Hefei 230032, China
| | - Yi-Chao Huang
- Key Laboratory of Environmental Toxicology of Anhui Higher Education Institutes, Anhui Medical University, Hefei 230032, China
| | - Hua Wang
- Key Laboratory of Environmental Toxicology of Anhui Higher Education Institutes, Anhui Medical University, Hefei 230032, China
| | - Wei Wei
- Key Laboratory of Anti-inflammatory & Immune Medicine, Education Ministry of China, Anhui Medical University, Hefei 230032, China.
| | - De-Xiang Xu
- Key Laboratory of Environmental Toxicology of Anhui Higher Education Institutes, Anhui Medical University, Hefei 230032, China.
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61
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Veltri AJ, D'Orazio KN, Lessen LN, Loll-Krippleber R, Brown GW, Green R. Distinct elongation stalls during translation are linked with distinct pathways for mRNA degradation. eLife 2022; 11:e76038. [PMID: 35894211 PMCID: PMC9352352 DOI: 10.7554/elife.76038] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2021] [Accepted: 07/25/2022] [Indexed: 11/13/2022] Open
Abstract
Key protein adapters couple translation to mRNA decay on specific classes of problematic mRNAs in eukaryotes. Slow decoding on non-optimal codons leads to codon-optimality-mediated decay (COMD) and prolonged arrest at stall sites leads to no-go decay (NGD). The identities of the decay factors underlying these processes and the mechanisms by which they respond to translational distress remain open areas of investigation. We use carefully designed reporter mRNAs to perform genetic screens and functional assays in Saccharomyces cerevisiae. We characterize the roles of Hel2, Syh1, and Smy2 in coordinating translational repression and mRNA decay on NGD reporter mRNAs, finding that Syh1 and, to a lesser extent its paralog Smy2, act in a distinct pathway from Hel2. This Syh1/Smy2-mediated pathway acts as a redundant, compensatory pathway to elicit NGD when Hel2-dependent NGD is impaired. Importantly, we observe that these NGD factors are not involved in the degradation of mRNAs enriched in non-optimal codons. Further, we establish that a key factor previously implicated in COMD, Not5, contributes modestly to the degradation of an NGD-targeted mRNA. Finally, we use ribosome profiling to reveal distinct ribosomal states associated with each reporter mRNA that readily rationalize the contributions of NGD and COMD factors to degradation of these reporters. Taken together, these results provide new insight into the role of Syh1 and Smy2 in NGD and into the ribosomal states that correlate with the activation of distinct pathways targeting mRNAs for degradation in yeast.
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Affiliation(s)
- Anthony J Veltri
- Department of Molecular Biology and Genetics, Howard Hughes Medical Institute, Johns Hopkins University School of Medicine, Baltimore, United States
| | - Karole N D'Orazio
- Department of Molecular Biology and Genetics, Howard Hughes Medical Institute, Johns Hopkins University School of Medicine, Baltimore, United States
| | - Laura N Lessen
- Department of Molecular Biology and Genetics, Howard Hughes Medical Institute, Johns Hopkins University School of Medicine, Baltimore, United States
| | | | - Grant W Brown
- Department of Biochemistry and Donnelly Centre, University of Toronto, Toronto, Canada
| | - Rachel Green
- Department of Molecular Biology and Genetics, Howard Hughes Medical Institute, Johns Hopkins University School of Medicine, Baltimore, United States
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62
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Farooq Z, Kusuma F, Burke P, Dufour CR, Lee D, Tabatabaei N, Toboz P, Radovani E, Greenblatt J, Rehman J, Class J, Khoutorsky A, Fonseca BD, Richner JM, Mercier E, Bourque G, Giguère V, Subramaniam AR, Han J, Tahmasebi S. The amino acid sensor GCN2 suppresses Terminal Oligopyrimidine (TOP) mRNA translation via La-related Protein 1 (LARP1). J Biol Chem 2022; 298:102277. [PMID: 35863436 PMCID: PMC9396407 DOI: 10.1016/j.jbc.2022.102277] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2022] [Revised: 07/10/2022] [Accepted: 07/11/2022] [Indexed: 11/16/2022] Open
Abstract
La-related protein 1 (LARP1) has been identified as a key translational inhibitor of terminal oligopyrimidine (TOP) mRNAs downstream of the nutrient sensing protein kinase complex, mTORC1. LARP1 exerts this inhibitory effect on TOP mRNA translation by binding to the mRNA cap and the adjacent 5′TOP motif, resulting in the displacement of the cap-binding protein eIF4E from TOP mRNAs. However, the involvement of additional signaling pathway in regulating LARP1-mediated inhibition of TOP mRNA translation is largely unexplored. In the present study, we identify a second nutrient sensing kinase GCN2 that converges on LARP1 to control TOP mRNA translation. Using chromatin-immunoprecipitation followed by massive parallel sequencing (ChIP-seq) analysis of activating transcription factor 4 (ATF4), an effector of GCN2 in nutrient stress conditions, in WT and GCN2 KO mouse embryonic fibroblasts, we determined that LARP1 is a GCN2-dependent transcriptional target of ATF4. Moreover, we identified GCN1, a GCN2 activator, participates in a complex with LARP1 on stalled ribosomes, suggesting a role for GCN1 in LARP1-mediated translation inhibition in response to ribosome stalling. Therefore, our data suggest that the GCN2 pathway controls LARP1 activity via two mechanisms: ATF4-dependent transcriptional induction of LARP1 mRNA and GCN1-mediated recruitment of LARP1 to stalled ribosomes.
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Affiliation(s)
- Zeenat Farooq
- Department of Pharmacology and Regenerative Medicine, University of Illinois College of Medicine, Chicago, IL, USA
| | - Fedho Kusuma
- Soonchunhyang Institute of Medi-bio Science (SIMS), Soonchunhyang University, Cheonan-si, Chungcheongnam-do 31151, Korea
| | - Phillip Burke
- Basic Sciences Division and Computational Biology Section of the Public Health Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
| | - Catherine R Dufour
- Goodman Cancer Research Centre, McGill University, Montréal, QC, H3A 1A3, Canada
| | - Duckgue Lee
- Soonchunhyang Institute of Medi-bio Science (SIMS), Soonchunhyang University, Cheonan-si, Chungcheongnam-do 31151, Korea
| | - Negar Tabatabaei
- Department of Pharmacology and Regenerative Medicine, University of Illinois College of Medicine, Chicago, IL, USA
| | - Phoenix Toboz
- Department of Pharmacology and Regenerative Medicine, University of Illinois College of Medicine, Chicago, IL, USA
| | - Ernest Radovani
- Donnelly Centre, University of Toronto, Toronto, ON M5S 3E1, Canada
| | - Jack Greenblatt
- Donnelly Centre, University of Toronto, Toronto, ON M5S 3E1, Canada
| | - Jalees Rehman
- Department of Pharmacology and Regenerative Medicine, University of Illinois College of Medicine, Chicago, IL, USA
| | - Jacob Class
- Department of Microbiology and Immunology, University of Illinois College of Medicine, Chicago, IL, USA
| | - Arkady Khoutorsky
- Department of Anesthesia and Faculty of Dentistry, McGill University, Montreal, QC H3A 0G1, Canada
| | | | - Justin M Richner
- Department of Microbiology and Immunology, University of Illinois College of Medicine, Chicago, IL, USA
| | - Eloi Mercier
- Canadian Centre for Computational Genomics, and McGill University and Genome Québec Innovation Center, Montréal, QC H3A 0G1, Canada
| | - Guillaume Bourque
- Canadian Centre for Computational Genomics, and McGill University and Genome Québec Innovation Center, Montréal, QC H3A 0G1, Canada
| | - Vincent Giguère
- Goodman Cancer Research Centre, McGill University, Montréal, QC, H3A 1A3, Canada
| | - Arvind R Subramaniam
- Basic Sciences Division and Computational Biology Section of the Public Health Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
| | - Jaeseok Han
- Soonchunhyang Institute of Medi-bio Science (SIMS), Soonchunhyang University, Cheonan-si, Chungcheongnam-do 31151, Korea.
| | - Soroush Tahmasebi
- Department of Pharmacology and Regenerative Medicine, University of Illinois College of Medicine, Chicago, IL, USA.
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63
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Lokdarshi A, von Arnim AG. Review: Emerging roles of the signaling network of the protein kinase GCN2 in the plant stress response. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2022; 320:111280. [PMID: 35643606 PMCID: PMC9197246 DOI: 10.1016/j.plantsci.2022.111280] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/28/2021] [Revised: 03/07/2022] [Accepted: 03/30/2022] [Indexed: 06/15/2023]
Abstract
The pan-eukaryotic protein kinase GCN2 (General Control Nonderepressible2) regulates the translation of mRNAs in response to external and metabolic conditions. Although GCN2 and its substrate, translation initiation factor 2 (eIF2) α, and several partner proteins are substantially conserved in plants, this kinase has assumed novel functions in plants, including in innate immunity and retrograde signaling between the chloroplast and cytosol. How exactly some of the biochemical paradigms of the GCN2 system have diverged in the green plant lineage is only partially resolved. Specifically, conflicting data underscore and cast doubt on whether GCN2 regulates amino acid biosynthesis; also whether phosphorylation of eIF2α can in fact repress global translation or activate mRNA specific translation via upstream open reading frames; and whether GCN2 is controlled in vivo by the level of uncharged tRNA. This review examines the status of research on the eIF2α kinase, GCN2, its function in the response to xenobiotics, pathogens, and abiotic stress conditions, and its rather tenuous role in the translational control of mRNAs.
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Affiliation(s)
- Ansul Lokdarshi
- Department of Biology, Valdosta State University, Valdosta, GA 31698, USA.
| | - Albrecht G von Arnim
- Department of Biochemistry & Cellular and Molecular Biology, The University of Tennessee, Knoxville, TN 37996-1939, USA; UT-ORNL Graduate School of Genome Science and Technology, The University of Tennessee, Knoxville, TN 37996-1939, USA.
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64
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Friedrich D, Marintchev A, Arthanari H. The metaphorical swiss army knife: The multitude and diverse roles of HEAT domains in eukaryotic translation initiation. Nucleic Acids Res 2022; 50:5424-5442. [PMID: 35552740 PMCID: PMC9177959 DOI: 10.1093/nar/gkac342] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 04/20/2022] [Accepted: 04/22/2022] [Indexed: 11/24/2022] Open
Abstract
Biomolecular associations forged by specific interaction among structural scaffolds are fundamental to the control and regulation of cell processes. One such structural architecture, characterized by HEAT repeats, is involved in a multitude of cellular processes, including intracellular transport, signaling, and protein synthesis. Here, we review the multitude and versatility of HEAT domains in the regulation of mRNA translation initiation. Structural and cellular biology approaches, as well as several biophysical studies, have revealed that a number of HEAT domain-mediated interactions with a host of protein factors and RNAs coordinate translation initiation. We describe the basic structural architecture of HEAT domains and briefly introduce examples of the cellular processes they dictate, including nuclear transport by importin and RNA degradation. We then focus on proteins in the translation initiation system featuring HEAT domains, specifically the HEAT domains of eIF4G, DAP5, eIF5, and eIF2Bϵ. Comparative analysis of their remarkably versatile interactions, including protein-protein and protein-RNA recognition, reveal the functional importance of flexible regions within these HEAT domains. Here we outline how HEAT domains orchestrate fundamental aspects of translation initiation and highlight open mechanistic questions in the area.
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Affiliation(s)
- Daniel Friedrich
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA, USA
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA, USA
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, USA
| | - Assen Marintchev
- Department of Physiology & Biophysics, Boston University School of Medicine, Boston, MA, USA
| | - Haribabu Arthanari
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA, USA
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, USA
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65
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The role of eIF2 phosphorylation in cell and organismal physiology: new roles for well-known actors. Biochem J 2022; 479:1059-1082. [PMID: 35604373 DOI: 10.1042/bcj20220068] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2022] [Revised: 04/21/2022] [Accepted: 04/25/2022] [Indexed: 02/06/2023]
Abstract
Control of protein synthesis (mRNA translation) plays key roles in shaping the proteome and in many physiological, including homeostatic, responses. One long-known translational control mechanism involves phosphorylation of initiation factor, eIF2, which is catalysed by any one of four protein kinases, which are generally activated in response to stresses. They form a key arm of the integrated stress response (ISR). Phosphorylated eIF2 inhibits eIF2B (the protein that promotes exchange of eIF2-bound GDP for GTP) and thus impairs general protein synthesis. However, this mechanism actually promotes translation of certain mRNAs by virtue of specific features they possess. Recent work has uncovered many previously unknown features of this regulatory system. Several studies have yielded crucial insights into the structure and control of eIF2, including that eIF2B is regulated by several metabolites. Recent studies also reveal that control of eIF2 and the ISR helps determine organismal lifespan and surprising roles in sensing mitochondrial stresses and in controlling the mammalian target of rapamycin (mTOR). The latter effect involves an unexpected role for one of the eIF2 kinases, HRI. Phosphoproteomic analysis identified new substrates for another eIF2 kinase, Gcn2, which senses the availability of amino acids. Several genetic disorders arise from mutations in genes for eIF2α kinases or eIF2B (i.e. vanishing white matter disease, VWM and microcephaly, epileptic seizures, microcephaly, hypogenitalism, diabetes and obesity, MEHMO). Furthermore, the eIF2-mediated ISR plays roles in cognitive decline associated with Alzheimer's disease. New findings suggest potential therapeutic value in interfering with the ISR in certain settings, including VWM, for example by using compounds that promote eIF2B activity.
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66
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Crawford RA, Ashe MP, Hubbard SJ, Pavitt GD. Cytosolic aspartate aminotransferase moonlights as a ribosome-binding modulator of Gcn2 activity during oxidative stress. eLife 2022; 11:73466. [PMID: 35621265 PMCID: PMC9191892 DOI: 10.7554/elife.73466] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Accepted: 05/25/2022] [Indexed: 11/13/2022] Open
Abstract
Regulation of translation is a fundamental facet of the cellular response to rapidly changing external conditions. Specific RNA-binding proteins (RBPs) co-ordinate the translational regulation of distinct mRNA cohorts during stress. To identify RBPs with previously under-appreciated roles in translational control, we used polysome profiling and mass spectrometry to identify and quantify proteins associated with translating ribosomes in unstressed yeast cells and during oxidative stress and amino acid starvation, which both induce the integrated stress response (ISR). Over 800 proteins were identified across polysome gradient fractions, including ribosomal proteins, translation factors, and many others without previously described translation-related roles, including numerous metabolic enzymes. We identified variations in patterns of PE in both unstressed and stressed cells and identified proteins enriched in heavy polysomes during stress. Genetic screening of polysome-enriched RBPs identified the cytosolic aspartate aminotransferase, Aat2, as a ribosome-associated protein whose deletion conferred growth sensitivity to oxidative stress. Loss of Aat2 caused aberrantly high activation of the ISR via enhanced eIF2α phosphorylation and GCN4 activation. Importantly, non-catalytic AAT2 mutants retained polysome association and did not show heightened stress sensitivity. Aat2 therefore has a separate ribosome-associated translational regulatory or 'moonlighting' function that modulates the ISR independent of its aspartate aminotransferase activity.
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Affiliation(s)
- Robert A Crawford
- Division of Molecular and Cellular Function, Faculty of Biology Medicine and Health, Manchester Academic Health Science Centre, The University of Manchester, Manchester, United Kingdom
| | - Mark P Ashe
- Division of Molecular and Cellular Function, Faculty of Biology Medicine and Health, Manchester Academic Health Science Centre, The University of Manchester, Manchester, United Kingdom
| | - Simon J Hubbard
- Division of Evolution, Infection and Genomics, Faculty of Biology Medicine and Health, Manchester Academic Health Science Centre, The University of Manchester, Manchester, United Kingdom
| | - Graham D Pavitt
- Division of Molecular and Cellular Function, Faculty of Biology Medicine and Health, Manchester Academic Health Science Centre, The University of Manchester, Manchester, United Kingdom
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67
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Simões V, Cizubu BK, Harley L, Zhou Y, Pajak J, Snyder NA, Bouvette J, Borgnia MJ, Arya G, Bartesaghi A, Silva GM. Redox-sensitive E2 Rad6 controls cellular response to oxidative stress via K63-linked ubiquitination of ribosomes. Cell Rep 2022; 39:110860. [PMID: 35613580 PMCID: PMC9215706 DOI: 10.1016/j.celrep.2022.110860] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Revised: 03/31/2022] [Accepted: 05/02/2022] [Indexed: 01/11/2023] Open
Abstract
Protein ubiquitination is an essential process that rapidly regulates protein synthesis, function, and fate in dynamic environments. Within its non-proteolytic functions, we showed that K63-linked polyubiquitinated conjugates heavily accumulate in yeast cells exposed to oxidative stress, stalling ribosomes at elongation. K63-ubiquitinated conjugates accumulate mostly because of redox inhibition of the deubiquitinating enzyme Ubp2; however, the role and regulation of ubiquitin-conjugating enzymes (E2) in this pathway remained unclear. Here, we show that the E2 Rad6 associates and modifies ribosomes during stress. We further demonstrate that Rad6 and its human homolog UBE2A are redox regulated by forming a reversible disulfide with the E1 ubiquitin-activating enzyme (Uba1). This redox regulation is part of a negative feedback regulation, which controls the levels of K63 ubiquitination under stress. Finally, we show that Rad6 activity is necessary to regulate translation, antioxidant defense, and adaptation to stress, thus providing an additional physiological role for this multifunctional enzyme.
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Affiliation(s)
- Vanessa Simões
- Department of Biology, Duke University, Durham, NC 27708, USA
| | | | - Lana Harley
- Department of Biology, Duke University, Durham, NC 27708, USA
| | - Ye Zhou
- Department of Computer Science, Department of Biochemistry, and Department of Electrical and Computer Engineering, Duke University, Durham, NC 27708, USA
| | - Joshua Pajak
- Department of Mechanical Engineering and Materials Science, Duke University, Durham, NC 27708, USA
| | - Nathan A Snyder
- Department of Biology, Duke University, Durham, NC 27708, USA
| | - Jonathan Bouvette
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Durham, NC 27709, USA
| | - Mario J Borgnia
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Durham, NC 27709, USA
| | - Gaurav Arya
- Department of Mechanical Engineering and Materials Science, Duke University, Durham, NC 27708, USA
| | - Alberto Bartesaghi
- Department of Computer Science, Department of Biochemistry, and Department of Electrical and Computer Engineering, Duke University, Durham, NC 27708, USA
| | - Gustavo M Silva
- Department of Biology, Duke University, Durham, NC 27708, USA.
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68
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Filbeck S, Cerullo F, Pfeffer S, Joazeiro CAP. Ribosome-associated quality-control mechanisms from bacteria to humans. Mol Cell 2022; 82:1451-1466. [PMID: 35452614 PMCID: PMC9034055 DOI: 10.1016/j.molcel.2022.03.038] [Citation(s) in RCA: 61] [Impact Index Per Article: 30.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2022] [Revised: 03/23/2022] [Accepted: 03/28/2022] [Indexed: 11/16/2022]
Abstract
Ribosome-associated quality-control (RQC) surveys incomplete nascent polypeptides produced by interrupted translation. Central players in RQC are the human ribosome- and tRNA-binding protein, NEMF, and its orthologs, yeast Rqc2 and bacterial RqcH, which sense large ribosomal subunits obstructed with nascent chains and then promote nascent-chain proteolysis. In canonical eukaryotic RQC, NEMF stabilizes the LTN1/Listerin E3 ligase binding to obstructed ribosomal subunits for nascent-chain ubiquitylation. Furthermore, NEMF orthologs across evolution modify nascent chains by mediating C-terminal, untemplated polypeptide elongation. In eukaryotes, this process exposes ribosome-buried nascent-chain lysines, the ubiquitin acceptor sites, to LTN1. Remarkably, in both bacteria and eukaryotes, C-terminal tails also have an extra-ribosomal function as degrons. Here, we discuss recent findings on RQC mechanisms and briefly review how ribosomal stalling is sensed upstream of RQC, including via ribosome collisions, from an evolutionary perspective. Because RQC defects impair cellular fitness and cause neurodegeneration, this knowledge provides a framework for pathway-related biology and disease studies.
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Affiliation(s)
- Sebastian Filbeck
- Zentrum für Molekulare Biologie der Universität Heidelberg, DKFZ-ZMBH Alliance, 69120 Heidelberg, Germany
| | - Federico Cerullo
- Zentrum für Molekulare Biologie der Universität Heidelberg, DKFZ-ZMBH Alliance, 69120 Heidelberg, Germany
| | - Stefan Pfeffer
- Zentrum für Molekulare Biologie der Universität Heidelberg, DKFZ-ZMBH Alliance, 69120 Heidelberg, Germany.
| | - Claudio A P Joazeiro
- Zentrum für Molekulare Biologie der Universität Heidelberg, DKFZ-ZMBH Alliance, 69120 Heidelberg, Germany; Department of Molecular Medicine, Scripps Florida, Jupiter, FL 33458, USA.
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69
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GCN2: roles in tumour development and progression. Biochem Soc Trans 2022; 50:737-745. [PMID: 35311890 PMCID: PMC9162460 DOI: 10.1042/bst20211252] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Revised: 03/01/2022] [Accepted: 03/07/2022] [Indexed: 12/12/2022]
Abstract
GCN2 (general control nonderepessible 2) is an eIF2α kinase responsible for entirely rewiring the metabolism of cells when they are put under amino acid starvation stress. Recently, there has been renewed interest in GCN2 as a potential oncotarget, with several studies reporting the development of small molecule inhibitors. The foundation of this work is built upon biochemical and cellular data which suggest GCN2 may be aberrantly overexpressed and is responsible for keeping cells on ‘life-support’ while tumours undergo significant nutritional stress during tumorigenesis, allowing cancer stem cells to develop chemotherapeutic resistance. However, most studies which have investigated the role of GCN2 in cancer have been conducted in various cancer model systems, often under a specific set of stresses, mutational backgrounds and drug cocktails. This review aims to comprehensively summarise the biochemical, molecular and cellular literature associated with GCN2 and its role in various cancers and determine whether a consensus can be developed to discern under which circumstances we may wish to target GCN2.
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70
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Liu J, Kasai S, Tatara Y, Yamazaki H, Mimura J, Mizuno S, Sugiyama F, Takahashi S, Sato T, Ozaki T, Tanji K, Wakabayashi K, Maeda H, Mizukami H, Shinkai Y, Kumagai Y, Tomita H, Itoh K. Inducible Systemic Gcn1 Deletion in Mice Leads to Transient Body Weight Loss upon Tamoxifen Treatment Associated with Decrease of Fat and Liver Glycogen Storage. Int J Mol Sci 2022; 23:3201. [PMID: 35328622 PMCID: PMC8949040 DOI: 10.3390/ijms23063201] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Revised: 03/09/2022] [Accepted: 03/15/2022] [Indexed: 02/06/2023] Open
Abstract
GCN1 is an evolutionarily-conserved ribosome-binding protein that mediates the amino acid starvation response as well as the ribotoxic stress response. We previously demonstrated that Gcn1 mutant mice lacking the GCN2-binding domain suffer from growth retardation and postnatal lethality via GCN2-independent mechanisms, while Gcn1-null mice die early in embryonic development. In this study, we explored the role of GCN1 in adult mice by generating tamoxifen-inducible conditional knockout (CKO) mice. Unexpectedly, the Gcn1 CKO mice showed body weight loss during tamoxifen treatment, which gradually recovered following its cessation. They also showed decreases in liver weight, hepatic glycogen and lipid contents, blood glucose and non-esterified fatty acids, and visceral white adipose tissue weight with no changes in food intake and viability. A decrease of serum VLDL suggested that hepatic lipid supply to the peripheral tissues was primarily impaired. Liver proteomic analysis revealed the downregulation of mitochondrial β-oxidation that accompanied increases of peroxisomal β-oxidation and aerobic glucose catabolism that maintain ATP levels. These findings show the involvement of GCN1 in hepatic lipid metabolism during tamoxifen treatment in adult mice.
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Affiliation(s)
- Jun Liu
- Department of Stress Response Science, Center for Advanced Medical Science, Hirosaki University Graduate School of Medicine, 5 Zaifu-cho, Hirosaki 036-8562, Japan; (J.L.); (Y.T.); (H.Y.); (J.M.); (T.S.); (K.I.)
| | - Shuya Kasai
- Department of Stress Response Science, Center for Advanced Medical Science, Hirosaki University Graduate School of Medicine, 5 Zaifu-cho, Hirosaki 036-8562, Japan; (J.L.); (Y.T.); (H.Y.); (J.M.); (T.S.); (K.I.)
| | - Yota Tatara
- Department of Stress Response Science, Center for Advanced Medical Science, Hirosaki University Graduate School of Medicine, 5 Zaifu-cho, Hirosaki 036-8562, Japan; (J.L.); (Y.T.); (H.Y.); (J.M.); (T.S.); (K.I.)
| | - Hiromi Yamazaki
- Department of Stress Response Science, Center for Advanced Medical Science, Hirosaki University Graduate School of Medicine, 5 Zaifu-cho, Hirosaki 036-8562, Japan; (J.L.); (Y.T.); (H.Y.); (J.M.); (T.S.); (K.I.)
| | - Junsei Mimura
- Department of Stress Response Science, Center for Advanced Medical Science, Hirosaki University Graduate School of Medicine, 5 Zaifu-cho, Hirosaki 036-8562, Japan; (J.L.); (Y.T.); (H.Y.); (J.M.); (T.S.); (K.I.)
| | - Seiya Mizuno
- Laboratory Animal Resource Center, University of Tsukuba, 1-1-1 Tennodai, Tsukuba 305-8575, Japan; (S.M.); (F.S.); (S.T.)
| | - Fumihiro Sugiyama
- Laboratory Animal Resource Center, University of Tsukuba, 1-1-1 Tennodai, Tsukuba 305-8575, Japan; (S.M.); (F.S.); (S.T.)
| | - Satoru Takahashi
- Laboratory Animal Resource Center, University of Tsukuba, 1-1-1 Tennodai, Tsukuba 305-8575, Japan; (S.M.); (F.S.); (S.T.)
| | - Tsubasa Sato
- Department of Stress Response Science, Center for Advanced Medical Science, Hirosaki University Graduate School of Medicine, 5 Zaifu-cho, Hirosaki 036-8562, Japan; (J.L.); (Y.T.); (H.Y.); (J.M.); (T.S.); (K.I.)
- Laboratory of Cell Biochemistry, Department of Biological Science, Graduate School of Science and Engineering, Iwate University, 4-3-5 Ueda, Morioka 020-8551, Japan;
| | - Taku Ozaki
- Laboratory of Cell Biochemistry, Department of Biological Science, Graduate School of Science and Engineering, Iwate University, 4-3-5 Ueda, Morioka 020-8551, Japan;
| | - Kunikazu Tanji
- Department of Neuropathology, Institute of Brain Science, Hirosaki University Graduate School of Medicine, 5 Zaifu-cho, Hirosaki 036-8562, Japan; (K.T.); (K.W.)
| | - Koichi Wakabayashi
- Department of Neuropathology, Institute of Brain Science, Hirosaki University Graduate School of Medicine, 5 Zaifu-cho, Hirosaki 036-8562, Japan; (K.T.); (K.W.)
| | - Hayato Maeda
- Faculty of Agriculture and Life Science, Hirosaki University, 3 Bunkyo-cho, Hirosaki 036-8561, Japan;
| | - Hiroki Mizukami
- Department of Pathology and Molecular Medicine, Hirosaki University Graduate School of Medicine, 5 Zaifu-cho, Hirosaki 036-8562, Japan;
| | - Yasuhiro Shinkai
- Environmental Biology Laboratory, Faculty of Medicine, University of Tsukuba, 1-1-1 Tennodai, Tsukuba 305-8575, Japan; (Y.S.); (Y.K.)
| | - Yoshito Kumagai
- Environmental Biology Laboratory, Faculty of Medicine, University of Tsukuba, 1-1-1 Tennodai, Tsukuba 305-8575, Japan; (Y.S.); (Y.K.)
| | - Hirofumi Tomita
- Department of Cardiology and Nephrology, Hirosaki University Graduate School of Medicine, 5 Zaifu-cho, Hirosaki 036-8562, Japan;
| | - Ken Itoh
- Department of Stress Response Science, Center for Advanced Medical Science, Hirosaki University Graduate School of Medicine, 5 Zaifu-cho, Hirosaki 036-8562, Japan; (J.L.); (Y.T.); (H.Y.); (J.M.); (T.S.); (K.I.)
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71
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Cerullo F, Filbeck S, Patil PR, Hung HC, Xu H, Vornberger J, Hofer FW, Schmitt J, Kramer G, Bukau B, Hofmann K, Pfeffer S, Joazeiro CAP. Bacterial ribosome collision sensing by a MutS DNA repair ATPase paralogue. Nature 2022; 603:509-514. [PMID: 35264791 DOI: 10.1038/s41586-022-04487-6] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Accepted: 01/28/2022] [Indexed: 12/12/2022]
Abstract
Ribosome stalling during translation is detrimental to cellular fitness, but how this is sensed and elicits recycling of ribosomal subunits and quality control of associated mRNA and incomplete nascent chains is poorly understood1,2. Here we uncover Bacillus subtilis MutS2, a member of the conserved MutS family of ATPases that function in DNA mismatch repair3, as an unexpected ribosome-binding protein with an essential function in translational quality control. Cryo-electron microscopy analysis of affinity-purified native complexes shows that MutS2 functions in sensing collisions between stalled and translating ribosomes and suggests how ribosome collisions can serve as platforms to deploy downstream processes: MutS2 has an RNA endonuclease small MutS-related (SMR) domain, as well as an ATPase/clamp domain that is properly positioned to promote ribosomal subunit dissociation, which is a requirement both for ribosome recycling and for initiation of ribosome-associated protein quality control (RQC). Accordingly, MutS2 promotes nascent chain modification with alanine-tail degrons-an early step in RQC-in an ATPase domain-dependent manner. The relevance of these observations is underscored by evidence of strong co-occurrence of MutS2 and RQC genes across bacterial phyla. Overall, the findings demonstrate a deeply conserved role for ribosome collisions in mounting a complex response to the interruption of translation within open reading frames.
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Affiliation(s)
- Federico Cerullo
- Zentrum für Molekulare Biologie der Universität Heidelberg, DKFZ-ZMBH Alliance, Heidelberg, Germany
| | - Sebastian Filbeck
- Zentrum für Molekulare Biologie der Universität Heidelberg, DKFZ-ZMBH Alliance, Heidelberg, Germany
| | - Pratik Rajendra Patil
- Zentrum für Molekulare Biologie der Universität Heidelberg, DKFZ-ZMBH Alliance, Heidelberg, Germany
| | - Hao-Chih Hung
- Zentrum für Molekulare Biologie der Universität Heidelberg, DKFZ-ZMBH Alliance, Heidelberg, Germany
| | - Haifei Xu
- Department of Molecular Medicine, Scripps Florida, Jupiter, FL, USA
| | - Julia Vornberger
- Zentrum für Molekulare Biologie der Universität Heidelberg, DKFZ-ZMBH Alliance, Heidelberg, Germany
| | - Florian W Hofer
- Zentrum für Molekulare Biologie der Universität Heidelberg, DKFZ-ZMBH Alliance, Heidelberg, Germany
| | - Jaro Schmitt
- Zentrum für Molekulare Biologie der Universität Heidelberg, DKFZ-ZMBH Alliance, Heidelberg, Germany
| | - Guenter Kramer
- Zentrum für Molekulare Biologie der Universität Heidelberg, DKFZ-ZMBH Alliance, Heidelberg, Germany
| | - Bernd Bukau
- Zentrum für Molekulare Biologie der Universität Heidelberg, DKFZ-ZMBH Alliance, Heidelberg, Germany
| | - Kay Hofmann
- Institute for Genetics, University of Cologne, Cologne, Germany
| | - Stefan Pfeffer
- Zentrum für Molekulare Biologie der Universität Heidelberg, DKFZ-ZMBH Alliance, Heidelberg, Germany.
| | - Claudio A P Joazeiro
- Zentrum für Molekulare Biologie der Universität Heidelberg, DKFZ-ZMBH Alliance, Heidelberg, Germany. .,Department of Molecular Medicine, Scripps Florida, Jupiter, FL, USA.
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72
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Amino Acid Signaling for TOR in Eukaryotes: Sensors, Transducers, and a Sustainable Agricultural fuTORe. Biomolecules 2022; 12:biom12030387. [PMID: 35327579 PMCID: PMC8945916 DOI: 10.3390/biom12030387] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2022] [Revised: 02/26/2022] [Accepted: 02/28/2022] [Indexed: 02/06/2023] Open
Abstract
Eukaryotic cells monitor and regulate metabolism through the atypical protein kinase target of rapamycin (TOR) regulatory hub. TOR is activated by amino acids in animals and fungi through molecular signaling pathways that have been extensively defined in the past ten years. Very recently, several studies revealed that TOR is also acutely responsive to amino acid metabolism in plants, but the mechanisms of amino acid sensing are not yet established. In this review, we summarize these discoveries, emphasizing the diversity of amino acid sensors in human cells and highlighting pathways that are indirectly sensitive to amino acids, i.e., how TOR monitors changes in amino acid availability without a bona fide amino acid sensor. We then discuss the relevance of these model discoveries to plant biology. As plants can synthesize all proteinogenic amino acids from inorganic precursors, we focus on the possibility that TOR senses both organic metabolites and inorganic nutrients. We conclude that an evolutionary perspective on nutrient sensing by TOR benefits both agricultural and biomedical science, contributing to ongoing efforts to generate crops for a sustainable agricultural future.
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73
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Houston L, Platten EM, Connelly SM, Wang J, Grayhack EJ. Frameshifting at collided ribosomes is modulated by elongation factor eEF3 and by integrated stress response regulators Gcn1 and Gcn20. RNA (NEW YORK, N.Y.) 2022; 28:320-339. [PMID: 34916334 PMCID: PMC8848926 DOI: 10.1261/rna.078964.121] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/26/2021] [Accepted: 11/25/2021] [Indexed: 06/14/2023]
Abstract
Ribosome stalls can result in ribosome collisions that elicit quality control responses, one function of which is to prevent ribosome frameshifting, an activity that entails the interaction of the conserved yeast protein Mbf1 with uS3 on colliding ribosomes. However, the full spectrum of factors that mediate frameshifting during ribosome collisions is unknown. To delineate such factors in the yeast Saccharomyces cerevisiae, we used genetic selections for mutants that affect frameshifting from a known ribosome stall site, CGA codon repeats. We show that the general translation elongation factor eEF3 and the integrated stress response (ISR) pathway components Gcn1 and Gcn20 modulate frameshifting in opposing manners. We found a mutant form of eEF3 that specifically suppressed frameshifting, but not translation inhibition by CGA codons. Thus, we infer that frameshifting at collided ribosomes requires eEF3, which facilitates tRNA-mRNA translocation and E-site tRNA release in yeast and other single cell organisms. In contrast, we found that removal of either Gcn1 or Gcn20, which bind collided ribosomes with Mbf1, increased frameshifting. Thus, we conclude that frameshifting is suppressed by Gcn1 and Gcn20, although these effects are not mediated primarily through activation of the ISR. Furthermore, we examined the relationship between eEF3-mediated frameshifting and other quality control mechanisms, finding that Mbf1 requires either Hel2 or Gcn1 to suppress frameshifting with wild-type eEF3. Thus, these results provide evidence of a direct link between translation elongation and frameshifting at collided ribosomes, as well as evidence that frameshifting is constrained by quality control mechanisms that act on collided ribosomes.
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Affiliation(s)
- Lisa Houston
- Department of Biochemistry and Biophysics, School of Medicine and Dentistry, University of Rochester, Rochester, New York 14642, USA
- Center for RNA Biology, University of Rochester, Rochester, New York 14642, USA
| | - Evan M Platten
- Department of Biochemistry and Biophysics, School of Medicine and Dentistry, University of Rochester, Rochester, New York 14642, USA
- Center for RNA Biology, University of Rochester, Rochester, New York 14642, USA
| | - Sara M Connelly
- Department of Biochemistry and Biophysics, School of Medicine and Dentistry, University of Rochester, Rochester, New York 14642, USA
- Center for RNA Biology, University of Rochester, Rochester, New York 14642, USA
| | - Jiyu Wang
- Department of Biochemistry and Biophysics, School of Medicine and Dentistry, University of Rochester, Rochester, New York 14642, USA
- Center for RNA Biology, University of Rochester, Rochester, New York 14642, USA
| | - Elizabeth J Grayhack
- Department of Biochemistry and Biophysics, School of Medicine and Dentistry, University of Rochester, Rochester, New York 14642, USA
- Center for RNA Biology, University of Rochester, Rochester, New York 14642, USA
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74
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Kim KQ, Zaher HS. Canary in a coal mine: collided ribosomes as sensors of cellular conditions. Trends Biochem Sci 2022; 47:82-97. [PMID: 34607755 PMCID: PMC8688274 DOI: 10.1016/j.tibs.2021.09.001] [Citation(s) in RCA: 35] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2021] [Revised: 08/30/2021] [Accepted: 09/03/2021] [Indexed: 02/06/2023]
Abstract
The recent discovery that collision of ribosomes triggers quality control and stress responses in eukaryotes has shifted the perspective of the field. Collided eukaryotic ribosomes adopt a unique structure, acting as a ubiquitin signaling platform for various response factors. While several of the signals that determine which downstream pathways are activated have been uncovered, we are only beginning to learn how the specificity for the activation of each process is achieved during collisions. This review will summarize those findings and how ribosome-associated factors act as molecular sentinels, linking aberrations in translation to the overall cellular state. Insights into how cells respond to ribosome collision events will provide greater understanding of the role of the ribosome in the maintenance of cellular homeostasis.
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Affiliation(s)
| | - Hani S. Zaher
- Correspondence to: , Department of Biology, Washington University in St. Louis, Campus Box 1137, One Brookings Drive, St. Louis, MO, USA 63130, Phone: (314) 935-7832, Fax: (314) 935-4432
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75
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Tauc M, Cougnon M, Carcy R, Melis N, Hauet T, Pellerin L, Blondeau N, Pisani DF. The eukaryotic initiation factor 5A (eIF5A1), the molecule, mechanisms and recent insights into the pathophysiological roles. Cell Biosci 2021; 11:219. [PMID: 34952646 PMCID: PMC8705083 DOI: 10.1186/s13578-021-00733-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2021] [Accepted: 12/14/2021] [Indexed: 11/29/2022] Open
Abstract
Since the demonstration of its involvement in cell proliferation, the eukaryotic initiation factor 5A (eIF5A) has been studied principally in relation to the development and progression of cancers in which the isoform A2 is mainly expressed. However, an increasing number of studies report that the isoform A1, which is ubiquitously expressed in normal cells, exhibits novel molecular features that reveal its new relationships between cellular functions and organ homeostasis. At a first glance, eIF5A can be regarded, among other things, as a factor implicated in the initiation of translation. Nevertheless, at least three specificities: (1) its extreme conservation between species, including plants, throughout evolution, (2) its very special and unique post-translational modification through the activating-hypusination process, and finally (3) its close relationship with the polyamine pathway, suggest that the role of eIF5A in living beings remains to be uncovered. In fact, and beyond its involvement in facilitating the translation of proteins containing polyproline residues, eIF5A is implicated in various physiological processes including ischemic tolerance, metabolic adaptation, aging, development, and immune cell differentiation. These newly discovered physiological properties open up huge opportunities in the clinic for pathologies such as, for example, the ones in which the oxygen supply is disrupted. In this latter case, organ transplantation, myocardial infarction or stroke are concerned, and the current literature defines eIF5A as a new drug target with a high level of potential benefit for patients with these diseases or injuries. Moreover, the recent use of genomic and transcriptomic association along with metadata studies also revealed the implication of eIF5A in genetic diseases. Thus, this review provides an overview of eIF5A from its molecular mechanism of action to its physiological roles and the clinical possibilities that have been recently reported in the literature.
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Affiliation(s)
- Michel Tauc
- LP2M, CNRS, Université Côte d'Azur, Nice, France. .,Laboratories of Excellence Ion Channel Science and Therapeutics, Nice, France. .,Laboratoire de Physiomédecine Moléculaire, UMR7370, Faculté de Médecine, CNRS, Université Côte d'Azur, 28 Avenue de Valombrose, 06107, Nice Cedex, France.
| | - Marc Cougnon
- LP2M, CNRS, Université Côte d'Azur, Nice, France.,Laboratories of Excellence Ion Channel Science and Therapeutics, Nice, France
| | - Romain Carcy
- Service de Réanimation Polyvalente et Service de Réanimation des Urgences Vitales, CHU Nice, Hôpital Pasteur 2, Nice, France
| | - Nicolas Melis
- Laboratory of Cellular and Molecular Biology, Center for Cancer Research, National Cancer Institute, Bethesda, MD, 20892, USA
| | - Thierry Hauet
- INSERM, IRTOMIT, CHU de Poitiers, Université de Poitiers, La Milétrie, Poitiers, France
| | - Luc Pellerin
- INSERM, IRTOMIT, CHU de Poitiers, Université de Poitiers, La Milétrie, Poitiers, France
| | - Nicolas Blondeau
- Laboratories of Excellence Ion Channel Science and Therapeutics, Nice, France.,IPMC, CNRS, Université Côte d'Azur, Valbonne, France
| | - Didier F Pisani
- LP2M, CNRS, Université Côte d'Azur, Nice, France.,Laboratories of Excellence Ion Channel Science and Therapeutics, Nice, France
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76
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Kershaw CJ, Jennings MD, Cortopassi F, Guaita M, Al-Ghafli H, Pavitt GD. GTP binding to translation factor eIF2B stimulates its guanine nucleotide exchange activity. iScience 2021; 24:103454. [PMID: 34877508 PMCID: PMC8633983 DOI: 10.1016/j.isci.2021.103454] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2021] [Revised: 10/26/2021] [Accepted: 11/11/2021] [Indexed: 01/23/2023] Open
Abstract
eIF2B is the guanine nucleotide exchange factor (GEF) required for cytoplasmic protein synthesis initiation in eukaryotes and its regulation within the integrated stress response (ISR). It activates its partner factor eIF2, thereby promoting translation initiation. Here we provide evidence through biochemical and genetic approaches that eIF2B can bind directly to GTP and this can enhance its rate of GEF activity toward eIF2–GDP in vitro. GTP binds to a subcomplex of the eIF2Bγ and ε subunits. The eIF2Bγ amino-terminal domain shares structural homology with hexose sugar phosphate pyrophosphorylase enzymes that bind specific nucleotides. A K66R mutation in eIF2Bγ is especially sensitive to guanine or GTP in a range of functional assays. Taken together, our data suggest eIF2Bγ may act as a sensor of purine nucleotide availability and thus modulate eIF2B activity and protein synthesis in response to fluctuations in cellular nucleotide levels. eIF2B, the GDP exchange factor for eIF2 in translation and its control, binds GTP GTP binding enhances the rate of eIF2B GEF activity toward eIF2–GDP in vitro A K66R mutation in yeast eIF2Bγ is sensitive to guanine in vivo or GTP in vitro eIF2B may act as a sensor of purine nucleotide availability
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Affiliation(s)
- Christopher J Kershaw
- Division of Molecular and Cellular Function, School of Biological Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester M13 9PT, UK
| | - Martin D Jennings
- Division of Molecular and Cellular Function, School of Biological Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester M13 9PT, UK
| | - Francesco Cortopassi
- Division of Molecular and Cellular Function, School of Biological Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester M13 9PT, UK
| | - Margherita Guaita
- Division of Molecular and Cellular Function, School of Biological Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester M13 9PT, UK
| | - Hawra Al-Ghafli
- Division of Molecular and Cellular Function, School of Biological Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester M13 9PT, UK
| | - Graham D Pavitt
- Division of Molecular and Cellular Function, School of Biological Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester M13 9PT, UK
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77
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Westrip CAE, Zhuang Q, Hall C, Eaton CD, Coleman ML. Developmentally regulated GTPases: structure, function and roles in disease. Cell Mol Life Sci 2021; 78:7219-7235. [PMID: 34664086 PMCID: PMC8629797 DOI: 10.1007/s00018-021-03961-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Revised: 08/13/2021] [Accepted: 09/28/2021] [Indexed: 01/01/2023]
Abstract
GTPases are a large superfamily of evolutionarily conserved proteins involved in a variety of fundamental cellular processes. The developmentally regulated GTP-binding protein (DRG) subfamily of GTPases consists of two highly conserved paralogs, DRG1 and DRG2, both of which have been implicated in the regulation of cell proliferation, translation and microtubules. Furthermore, DRG1 and 2 proteins both have a conserved binding partner, DRG family regulatory protein 1 and 2 (DFRP1 and DFRP2), respectively, that prevents them from being degraded. Similar to DRGs, the DFRP proteins have also been studied in the context of cell growth control and translation. Despite these proteins having been implicated in several fundamental cellular processes they remain relatively poorly characterized, however. In this review, we provide an overview of the structural biology and biochemistry of DRG GTPases and discuss current understanding of DRGs and DFRPs in normal physiology, as well as their emerging roles in diseases such as cancer.
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Affiliation(s)
- Christian A E Westrip
- Tumour Oxygenase Group, Institute of Cancer and Genomic Sciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
| | - Qinqin Zhuang
- Tumour Oxygenase Group, Institute of Cancer and Genomic Sciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
- Institute of Inflammation and Ageing, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
| | - Charlotte Hall
- Tumour Oxygenase Group, Institute of Cancer and Genomic Sciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
| | - Charlotte D Eaton
- Tumour Oxygenase Group, Institute of Cancer and Genomic Sciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
- Neurological Surgery, School of Medicine, University of California, 1450 Third St, San Francisco, CA, 94158, USA
| | - Mathew L Coleman
- Tumour Oxygenase Group, Institute of Cancer and Genomic Sciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK.
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78
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Egorov AA, Makeeva DS, Makarova NE, Bykov DA, Hrytseniuk YS, Mitkevich OV, Urakov VN, Alexandrov AI, Kulakovskiy IV, Dmitriev SE. Ribo-Seq and RNA-Seq of TMA46 ( DFRP1) and GIR2 ( DFRP2) knockout yeast strains. F1000Res 2021; 10:1162. [PMID: 34900236 PMCID: PMC8637242 DOI: 10.12688/f1000research.74727.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 11/11/2021] [Indexed: 11/20/2022] Open
Abstract
In eukaryotes, stalled and collided ribosomes are recognized by several conserved multicomponent systems, which either block protein synthesis in situ and resolve the collision locally, or trigger a general stress response. Yeast ribosome-binding GTPases RBG1 (DRG1 in mammals) and RBG2 (DRG2) form two distinct heterodimers with TMA46 (DFRP1) and GIR2 (DFRP2), respectively, both involved in mRNA translation. Accumulated evidence suggests that the dimers play partially redundant roles in elongation processivity and resolution of ribosome stalling and collision events, as well as in the regulation of GCN1-mediated signaling involved in ribosome-associated quality control (RQC). They also genetically interact with SLH1 (ASCC3) helicase, a key component of RQC trigger (RQT) complex disassembling collided ribosomes. Here, we present RNA-Seq and ribosome profiling (Ribo-Seq) data from S. cerevisiae strains with individual deletions of the TMA46 and GIR2 genes. Raw RNA-Seq and Ribo-Seq data as well as gene-level read counts are available in NCBI Gene Expression Omnibus (GEO) repository under GEO accession GSE185458 and GSE185286.
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Affiliation(s)
- Artyom A. Egorov
- Phystech School of Biological and Medical Physics, Moscow Institute of Physics and Technology (State University), Dolgoprudny, 141700, Russian Federation
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119234, Russian Federation
- Sirius University of Science and Technology, Sochi, 354340, Russian Federation
| | - Desislava S. Makeeva
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119234, Russian Federation
- Sirius University of Science and Technology, Sochi, 354340, Russian Federation
| | - Nadezhda E. Makarova
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119234, Russian Federation
- Sirius University of Science and Technology, Sochi, 354340, Russian Federation
- Faculty of Bioengineering and Bioinformatics, Lomonosov Moscow State University, Moscow, 119234, Russian Federation
| | - Dmitri A. Bykov
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119234, Russian Federation
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Moscow, 119991, Russian Federation
| | - Yanislav S. Hrytseniuk
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119234, Russian Federation
- Department of Chemistry, Lomonosov Moscow State University, Moscow, 119234, Russian Federation
| | - Olga V. Mitkevich
- Bach Institute of Biochemistry, FRC of Biotechnology of the Russian Academy of Sciences, Moscow, 119071, Russian Federation
| | - Valery N. Urakov
- Bach Institute of Biochemistry, FRC of Biotechnology of the Russian Academy of Sciences, Moscow, 119071, Russian Federation
| | - Alexander I. Alexandrov
- Bach Institute of Biochemistry, FRC of Biotechnology of the Russian Academy of Sciences, Moscow, 119071, Russian Federation
| | - Ivan V. Kulakovskiy
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119234, Russian Federation
- Sirius University of Science and Technology, Sochi, 354340, Russian Federation
- Institute of Protein Research, Russian Academy of Sciences, Pushchino, 142290, Russian Federation
| | - Sergey E. Dmitriev
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119234, Russian Federation
- Sirius University of Science and Technology, Sochi, 354340, Russian Federation
- Faculty of Bioengineering and Bioinformatics, Lomonosov Moscow State University, Moscow, 119234, Russian Federation
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Moscow, 119991, Russian Federation
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79
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Zeng F, Li X, Pires-Alves M, Chen X, Hawk CW, Jin H. Conserved heterodimeric GTPase Rbg1/Tma46 promotes efficient translation in eukaryotic cells. Cell Rep 2021; 37:109877. [PMID: 34706231 DOI: 10.1016/j.celrep.2021.109877] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Revised: 06/21/2021] [Accepted: 09/30/2021] [Indexed: 11/19/2022] Open
Abstract
Conserved developmentally regulated guanosine triphosphate (GTP)-binding proteins (Drgs) and their binding partner Drg family regulatory proteins (Dfrps) are important for embryonic development, cellular growth control, differentiation, and proliferation. Here, we report that the yeast Drg1/Dfrp1 ortholog Rbg1/Tma46 facilitates translational initiation, elongation, and termination by suppressing prolonged ribosome pausing. Consistent with the genome-wide observations, deletion of Rbg1 exacerbates the growth defect resulting from translation stalling, and Rbg1 stabilizes mRNAs against no-go decay. Furthermore, we provide a cryoelectron microscopy (cryo-EM) structure of the 80S ribosome bound with Rbg1/Tma46 that reveals the molecular interactions responsible for Rbg1/Tma46 function. The Rbg1 subunit binds to the GTPase association center of the ribosome and the A-tRNA, and the N-terminal zinc finger domain of the Tma46 subunit binds to the 40S, establishing an interaction critical for the ribosomal association. Our results answer the fundamental question of how a paused ribosome resumes translation and show that Drg1/Dfrp1 play a critical role in ensuring orderly translation.
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Affiliation(s)
- Fuxing Zeng
- Department of Biochemistry, University of Illinois at Urbana-Champaign, 600 S. Mathews Avenue, Urbana, IL 61801, USA; Department of Biology, School of Life Sciences, Southern University of Science and Technology, No. 1088 Xueyuan Blvd., Shenzhen 518055, People's Republic of China
| | - Xin Li
- Department of Biology, School of Life Sciences, Southern University of Science and Technology, No. 1088 Xueyuan Blvd., Shenzhen 518055, People's Republic of China
| | - Melissa Pires-Alves
- Department of Biochemistry, University of Illinois at Urbana-Champaign, 600 S. Mathews Avenue, Urbana, IL 61801, USA
| | - Xin Chen
- Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, 600 S. Mathews Avenue, Urbana, IL 61801, USA
| | - Christopher W Hawk
- Department of Biochemistry, University of Illinois at Urbana-Champaign, 600 S. Mathews Avenue, Urbana, IL 61801, USA
| | - Hong Jin
- Department of Biochemistry, University of Illinois at Urbana-Champaign, 600 S. Mathews Avenue, Urbana, IL 61801, USA; Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, 600 S. Mathews Avenue, Urbana, IL 61801, USA; Carl R. Woese Institute for Genomic Biology, 1206 West Gregory Drive, University of Illinois at Urbana-Champaign, 600 S. Mathews Avenue, Urbana, IL 61801, USA.
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80
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Andreev DE, Smirnova VV, Shatsky IN. Modifications of Ribosome Profiling that Provide New Data on the Translation Regulation. BIOCHEMISTRY (MOSCOW) 2021; 86:1095-1106. [PMID: 34565313 DOI: 10.1134/s0006297921090054] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Ribosome profiling (riboseq) has opened the possibilities for the genome-wide studies of translation in all living organisms. This method is based on deep sequencing of mRNA fragments protected by the ribosomes from hydrolysis by ribonucleases, the so-called ribosomal footprints (RFPs). Ribosomal profiling together with RNA sequencing allows not only to identify with a reasonable accuracy translated reading frames in the transcriptome, but also to track changes in gene expression in response to various stimuli. Notably, ribosomal profiling in its classical version has certain limitations. The size of the selected mRNA fragments is 25-35 nts, while RFPs of other sizes are usually omitted from analysis. Also, ribosomal profiling "averages" the data from all ribosomes and does not allow to study specific ribosomal complexes associated with particular translation factors. However, recently developed modifications of ribosomal profiling provide answers to a number of questions. Thus, it has become possible to analyze not only elongating, but also scanning and reinitiating ribosomes, to study events associated with the collision of ribosomes during mRNA translation, to discover new ways of cotranslational assembly of multisubunit protein complexes during translation, and to selectively isolate ribosomal complexes associated with certain protein factors. New data obtained using these modified approaches provide a better understanding of the mechanisms of translation regulation and the functional roles of translational apparatus components.
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Affiliation(s)
- Dmitry E Andreev
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119992, Russia.,Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry of the Russian Academy of Sciences, Moscow, 117997, Russia
| | - Viktoriya V Smirnova
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119992, Russia
| | - Ivan N Shatsky
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119992, Russia.
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81
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Nwokoye EC, AlNaseem E, Crawford RA, Castelli LM, Jennings MD, Kershaw CJ, Pavitt GD. Overlapping regions of Caf20 mediate its interactions with the mRNA-5'cap-binding protein eIF4E and with ribosomes. Sci Rep 2021; 11:13467. [PMID: 34188131 PMCID: PMC8242001 DOI: 10.1038/s41598-021-92931-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Accepted: 06/03/2021] [Indexed: 02/06/2023] Open
Abstract
By interacting with the mRNA 5' cap, the translation initiation factor eIF4E plays a critical role in selecting mRNAs for protein synthesis in eukaryotic cells. Caf20 is a member of the family of proteins found across eukaryotes termed 4E-BPs, which compete with eIF4G for interaction with eIF4E. Caf20 independently interacts with ribosomes. Thus, Caf20 modulates the mRNA selection process via poorly understood mechanisms. Here we performed unbiased mutagenesis across Caf20 to characterise which regions of Caf20 are important for interaction with eIF4E and with ribosomes. Caf20 binding to eIF4E is entirely dependent on a canonical motif shared with other 4E-BPs. However, binding to ribosomes is weakened by mutations throughout the protein, suggesting an extended binding interface that partially overlaps with the eIF4E-interaction region. By using chemical crosslinking, we identify a potential ribosome interaction region on the ribosome surface that spans both small and large subunits and is close to a known interaction site of eIF3. The function of ribosome binding by Caf20 remains unclear.
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Affiliation(s)
- Ebelechukwu C Nwokoye
- Division of Molecular and Cellular Function, School of Biological Sciences, Faculty of Biology, Medicine and Health, Manchester Academic Health Science Centre, The University of Manchester, Manchester, M13 9PT, UK.,Department of Botany, Nnamdi Azikiwe University, Awka, Nigeria
| | - Eiman AlNaseem
- Division of Molecular and Cellular Function, School of Biological Sciences, Faculty of Biology, Medicine and Health, Manchester Academic Health Science Centre, The University of Manchester, Manchester, M13 9PT, UK
| | - Robert A Crawford
- Division of Molecular and Cellular Function, School of Biological Sciences, Faculty of Biology, Medicine and Health, Manchester Academic Health Science Centre, The University of Manchester, Manchester, M13 9PT, UK
| | - Lydia M Castelli
- Division of Molecular and Cellular Function, School of Biological Sciences, Faculty of Biology, Medicine and Health, Manchester Academic Health Science Centre, The University of Manchester, Manchester, M13 9PT, UK.,Department of Neuroscience, Sheffield Institute for Translational Neuroscience (SITraN), University of Sheffield, Sheffield, S10 2HQ, UK
| | - Martin D Jennings
- Division of Molecular and Cellular Function, School of Biological Sciences, Faculty of Biology, Medicine and Health, Manchester Academic Health Science Centre, The University of Manchester, Manchester, M13 9PT, UK
| | - Christopher J Kershaw
- Division of Molecular and Cellular Function, School of Biological Sciences, Faculty of Biology, Medicine and Health, Manchester Academic Health Science Centre, The University of Manchester, Manchester, M13 9PT, UK
| | - Graham D Pavitt
- Division of Molecular and Cellular Function, School of Biological Sciences, Faculty of Biology, Medicine and Health, Manchester Academic Health Science Centre, The University of Manchester, Manchester, M13 9PT, UK.
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Iron in Translation: From the Beginning to the End. Microorganisms 2021; 9:microorganisms9051058. [PMID: 34068342 PMCID: PMC8153317 DOI: 10.3390/microorganisms9051058] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Revised: 05/10/2021] [Accepted: 05/11/2021] [Indexed: 12/16/2022] Open
Abstract
Iron is an essential element for all eukaryotes, since it acts as a cofactor for many enzymes involved in basic cellular functions, including translation. While the mammalian iron-regulatory protein/iron-responsive element (IRP/IRE) system arose as one of the first examples of translational regulation in higher eukaryotes, little is known about the contribution of iron itself to the different stages of eukaryotic translation. In the yeast Saccharomyces cerevisiae, iron deficiency provokes a global impairment of translation at the initiation step, which is mediated by the Gcn2-eIF2α pathway, while the post-transcriptional regulator Cth2 specifically represses the translation of a subgroup of iron-related transcripts. In addition, several steps of the translation process depend on iron-containing enzymes, including particular modifications of translation elongation factors and transfer RNAs (tRNAs), and translation termination by the ATP-binding cassette family member Rli1 (ABCE1 in humans) and the prolyl hydroxylase Tpa1. The influence of these modifications and their correlation with codon bias in the dynamic control of protein biosynthesis, mainly in response to stress, is emerging as an interesting focus of research. Taking S. cerevisiae as a model, we hereby discuss the relevance of iron in the control of global and specific translation steps.
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83
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Yip MCJ, Shao S. Detecting and Rescuing Stalled Ribosomes. Trends Biochem Sci 2021; 46:731-743. [PMID: 33966939 DOI: 10.1016/j.tibs.2021.03.008] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Revised: 03/18/2021] [Accepted: 03/30/2021] [Indexed: 11/24/2022]
Abstract
Ribosomes that stall inappropriately during protein synthesis harbor proteotoxic components linked to cellular stress and neurodegenerative diseases. Molecular mechanisms that rescue stalled ribosomes must selectively detect rare aberrant translational complexes and process the heterogeneous components. Ribosome-associated quality control pathways eliminate problematic messenger RNAs and nascent proteins on stalled translational complexes. In addition, recent studies have uncovered general principles of stall recognition upstream of quality control pathways and fail-safe mechanisms that ensure nascent proteome integrity. Here, we discuss developments in our mechanistic understanding of the detection and rescue of stalled ribosomal complexes in eukaryotes.
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Affiliation(s)
- Matthew C J Yip
- Department of Cell Biology, Harvard Medical School, 240 Longwood Avenue, Boston, MA 02115, USA
| | - Sichen Shao
- Department of Cell Biology, Harvard Medical School, 240 Longwood Avenue, Boston, MA 02115, USA.
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